Honestly, I would say yes to getting both, but if you are getting a 2 door Sport that will be 100% on (flat) road, you don't "need" the 3.73's if you know you will never go with larger wheels. However, I would still consider getting them.

If you live in hilly country, hell yea. 3.21 gears are for the flat lands. transmitions get worked in and out of gear which causes more wear n tear. If it were a stick ide say maybe but otherwise, get the gears! More torque = more power to pull. engine doesnt have to work as hard, etc.

If I were buying a Jeep and I wasn't planning on upsizing the tires over the stock 32's, I would go with the 3.73 gears without exception.

As far as the limited slip (anti-spin), I would be flexible on. If it has it, great. If not, it's not a deal breaker. For strictly on road driving, the traction control system is probably enough to help you the few times you need it. But having the limited slip is certainly not a bad thing. If you're looking at one on the lot (which you would have to for a 2013 these days) I wouldn't hesitate to pay for it if the Jeep has it. I also wouldn't pass over the Jeep if it didn't.

The ASD will come in handy if you have to turn into traffic in the rain/snow, the electronics will work but will also limit power if you start really spinning one tire until it gets up to speed. Hardcore off roaders wont want the clutch ASD, but they would probably get into a rubicon with the lockers..

I have a '13 2 door auto with the 3.73s and if I was to keep the stock tires I wouldnt mind the 3.21. The 5 speed auto had a pretty low 1st gear and the 3.73 is almost a bit of overkill IMO.

I drove both 3.21 w/o LSD and 3.73 w/ LSD (and other combos) during my search. 3.73 is definitely the better choice in almost every situation. LSD is nice to have but, IMO, not a deal breaker if you find one with everything else you want.

First of all, it has for years been nick-named "Trash-Lok" for a reason and that's because the clutches wear out over time and stop working and then break and scatter. Two days ago I popped open the rear diff on a Ram pickup that my buddy bought and it was ordered with the limited slip option. There were big pieces of metal laying in the bottom of the case. Thank God they didn't get thrown into the ring gear or spider gears when they broke. Who wants this junk in their rear axles for an extra cost of hundreds of dollars??

Second, you can buy a helical limited slip or lunchbox style locker for roughly the same money and have something that will actually work.

Third, the electronic traction control on JKs works better than any limited slip ever did. With both open diffs I was able to go places that other older Jeeps couldn't follow.

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~Lots of modded Jeeps and a Toyota 4Runner~
My favorite quote from the press release.. sad but true: "Chrysler claims its products, especially the Jeeps, can handle all sorts of terrible conditions, churning through muddy swamps, climbing mountains, and crossing rivers. Turns out they cannot even handle a car wash."

If you don't see a lot of snow/ice/rain where you live, LSD won't be as much of a priority.

Trac-Lok vs aftermarket is a different argument. I thought about passing on Trac-Lok and going aftermarket, but for how I use the Jeep....it simply wasn't worth it.

If I was going to do a lot of off-roading, but still wanted LSD, I would pass on Trac-Lok and go with an aftermarket TrueTrac. But for just city driving with the occasional gravel or fire road once every 6 months, Trac-Loc is just fine for $295 MSRP and covered under the factory warranty.

Trac-Lok gets the name "Trash-Lok" because it is useless for off-roading...especially compared to an Eaton or something. But there are not a lot of Wrangler owners that are going to open up the pumpkin on brand new Jeep to install an Eaton on a rig that will be stock and used on pavement 99.99% of the time. With light duty use, the clutch packs will last quite a while.

For me 3.73 would be a must have. If you plan on going for bigger tires it will really be worth it.

I've getting gears tomorrow and was wrestling the last two weeks on if I should add a truetrac but in the end every time I see a situation on the trail where I want more traction a locker would be of much more benefit. This is from a strictly offroad point of view. I opted to skip the truetrac and just add a locker when I add onboard air.

I was planning to get the LSD, since we occasionally get snow, and it seemed like it would be better than a totally open diff. Keeping in mind that, it is likely to stay 90% on the road, and then be logging road and (potentially poorly maintained) forest roads otherwise.

I am curious if getting the factory LSD limits my options though. I know you can add an aftermarket LSD (or a locker) if you don't get one from the factory. If you DO get the factory LSD, how hard is it to replace it with an aftermarket one? Is it just about the same as adding the aftermarket one to stock, or does it add a lot more hassle? Is there an aftermarket option like the TJ Rubicons, that is a combination of LSD and locker?

If factory LSD makes things more complicated later, or if I could get a combination LSD/locker, I'd probably do that. Yeah, it is overkill, but so is getting a Wrangler start with. Being able to customize and indulge in some overkill is the whole reason I chose the Wrangler in the first place.

I was planning to get the LSD, since we occasionally get snow, and it seemed like it would be better than a totally open diff. Keeping in mind that, it is likely to stay 90% on the road, and then be logging road and (potentially poorly maintained) forest roads otherwise.

I am curious if getting the factory LSD limits my options though. I know you can add an aftermarket LSD (or a locker) if you don't get one from the factory. If you DO get the factory LSD, how hard is it to replace it with an aftermarket one? Is it just about the same as adding the aftermarket one to stock, or does it add a lot more hassle? Is there an aftermarket option like the TJ Rubicons, that is a combination of LSD and locker?

If factory LSD makes things more complicated later, or if I could get a combination LSD/locker, I'd probably do that. Yeah, it is overkill, but so is getting a Wrangler start with. Being able to customize and indulge in some overkill is the whole reason I chose the Wrangler in the first place.

If I remember correctly, adding LSD from the factory DOES make it a bit more difficult to add an aftermarket LSD down the road.

How hard is an aftermarket install if you are moderately handy (though relatively new to working on cars)? I do have access to a lift if that helps/is necessary.

Of course, I also have access to a good mechanic, too, but learning about things myself is one of the things I wanted to do with the Wrangler.

If you're just replacing the carrier and not changing gears, it's not terribly hard. You need an install kit with new carrier bearings and shims. You need to swap the ring gear from one case to the other and put the new carrier in. Once you do that you need to ensure you get the correct amount of backlash and that the gears still mesh correctly. A dial indicator is about the only specialty tool you need. Though having access a press to get the new bearings on the new carrier certainly helps.

If you're going to regear at the same time you need a few more tools than that. You need to set the pinion depth correctly, which involves making setup bearings or pressing and pulling the bearings a couple of times. Beyond that, you need a big enough wrench to crush the crush sleeve to properly set the bearing preload on the pinion. You need several hundred foot pounds to crush that sleeve. When I participated in doing my gears we needed a 5 foot long cheater pipe on a 3/4" drive socket and still had to put everything into it to get the torque we needed. If you've never done it before and don't know anyone who has, you're better off letting a shop handle it.

Have to say that I've driven my JKU in rain, snow, ice, mud, and soft sand (mostly on the road) and I've never gotten stuck or felt that I needed an LSD. It does amazing with open diffs and I don't regret passing on the option when I ordered. To me, it was just another repair item.

After 20k miles, I'm very happy with the 3.73s. On the road, even with the stock 17" setup, the performance is just right and I still net 20 mpg.

First of all, it has for years been nick-named "Trash-Lok" for a reason and that's because the clutches wear out over time and stop working and then break and scatter. Two days ago I popped open the rear diff on a Ram pickup that my buddy bought and it was ordered with the limited slip option. There were big pieces of metal laying in the bottom of the case. Thank God they didn't get thrown into the ring gear or spider gears when they broke. Who wants this junk in their rear axles for an extra cost of hundreds of dollars??

Second, you can buy a helical limited slip or lunchbox style locker for roughly the same money and have something that will actually work.

Third, the electronic traction control on JKs works better than any limited slip ever did. With both open diffs I was able to go places that other older Jeeps couldn't follow.

The electronic traction control will get way more life out of a clutch LSD as well. Number one clutch type posi killer is spinning one tire hard and the other not spinning at all. In normal driving (as long as both of your tires on the axle are the same diameter anyhow) a clutch type should easily go 100K miles.

I'm not saying the Jeep ASD is the best on earth, if you are wheeling all it takes is the one time where the clutches dont hold and you give it a lot of throttle to glaze the clutches and from there its a downhill slide - but - the electronic traction control you mentioned should stop that from happening and help an ASD go anywhere an open will.

Torsen/helical and detroit locker diffs can fail pretty spectacularly as well if you have enough torque

Having LSD is a plus in winter or wet conditions. There isn't much of a downside to it. Now, if you live in Texas or Arizona or southern Cali or someplace like that...winter driving does not apply.

Everyone thinks Arizona is hot with tons of cactus (lol). Well, I live near Flagstaff which is over 7,000 ft and we get tons of snow. Also, there is Big Bear and Mt Baldy in S. Calif. that get a lot of snow as well. I don't know about Texas, however. Just thought I'd enlighten everyone about Arizona and S. Calif.

Everyone thinks Arizona is hot with tons of cactus (lol). Well, I live near Flagstaff which is over 7,000 ft and we get tons of snow. Also, there is Big Bear and Mt Baldy in S. Calif. that get a lot of snow as well. I don't know about Texas, however. Just thought I'd enlighten everyone about Arizona and S. Calif.

I went with the 3.73 gears and LSD. Get them both.

The pan handle of Texas gets lots of snow every year also. I don't think people from the north east realize just how big the states are and how much different terrain they have to them once you get past the Mississippi. I hear you "you are from Texas so you only know about the desert" when the truth is I have to drive 7 hours before I start to get there. Its all river bottoms and pine trees where I live.

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I'm here to participate. I didnt come all this way just to watch.

Everyone thinks Arizona is hot with tons of cactus (lol). Well, I live near Flagstaff which is over 7,000 ft and we get tons of snow. Also, there is Big Bear and Mt Baldy in S. Calif. that get a lot of snow as well. I don't know about Texas, however. Just thought I'd enlighten everyone about Arizona and S. Calif.

I went with the 3.73 gears and LSD. Get them both.

Fair enough.... I have land in New Mexico...and there is indeed snow there.

Quote:

Originally Posted by WatchThis!

The pan handle of Texas gets lots of snow every year also. I don't think people from the north east realize just how big the states are and how much different terrain they have to them once you get past the Mississippi. I hear you "you are from Texas so you only know about the desert" when the truth is I have to drive 7 hours before I start to get there. Its all river bottoms and pine trees where I live.

I used to live in Dallas and Garland, and spent a good chunk of time in Houston where some of my family is still at (when they are not visiting Oklahoma).....which is where my POV is coming from....so I'm just generalizing a bit.
I know Texas isn't the Mojave...especially in east Texas where the humidity will suffocate you. I've driven to and through Texas more times than I can count. I'm just saying, winter in Texas isn't like winter in Chicago or Iowa. But to be honest, as of late....our winters have gotten pretty mild. When I was a kid in Iowa...when the first big snow hit (late November, early December), that snow didn't go away until March....sometime after the basketball state tournament (always the last big snow of the year for some reason).